package au.org.nh.pdfgen;

/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

/* $Id$ */

//Java
import java.io.ByteArrayOutputStream;

import javax.xml.transform.Result;
import javax.xml.transform.Source;
import javax.xml.transform.Transformer;
import javax.xml.transform.TransformerFactory;
import javax.xml.transform.URIResolver;
import javax.xml.transform.sax.SAXResult;
import javax.xml.transform.stream.StreamSource;

import org.apache.fop.apps.FOUserAgent;
import org.apache.fop.apps.Fop;
import org.apache.fop.apps.FopFactory;
import org.apache.fop.apps.MimeConstants;

/**
 * This class demonstrates the conversion of an XML file to PDF using JAXP
 * (XSLT) and FOP (XSL-FO).
 */
public class FOPPDFGeneratorImpl implements PDFGenerator {

	@Override
	public byte[] generate(final StreamSource xmlsource,
			final StreamSource xslsource, final URIResolver uriResolver) {
		byte[] content = null;

		// configure fopFactory as desired
		final FopFactory fopFactory = FopFactory.newInstance();
		fopFactory.setURIResolver(uriResolver);
		final FOUserAgent foUserAgent = fopFactory.newFOUserAgent();
		// configure foUserAgent as desired
		ByteArrayOutputStream out = null;
		try {
			// Setup output
			out = new ByteArrayOutputStream();

			// Construct fop with desired output format
			final Fop fop = fopFactory.newFop(MimeConstants.MIME_PDF,
					foUserAgent, out);

			// Setup XSLT
			final TransformerFactory factory = TransformerFactory.newInstance();
			final Transformer transformer = factory.newTransformer(xslsource);

			// Set the value of a <param> in the stylesheet
			transformer.setParameter("versionParam", "2.0");

			// Setup input for XSLT transformation
			final Source src = xmlsource;

			// Resulting SAX events (the generated FO) must be piped through
			// to FOP
			final Result res = new SAXResult(fop.getDefaultHandler());

			// Start XSLT transformation and FOP processing
			transformer.transform(src, res);
			content = out.toByteArray();
			out.close();
		} catch (final Exception e) {
			e.printStackTrace();
		}
		return content;
	}

}
